For forming and portioning hamburgers, other ground meat, fish, vegetables e.g., in the commissaries, plants and kitchens of food processors, airline and institutional food service companies, fast food restaurant franchisors and other suppliers and the like, methods and apparatus have been developed and placed in widespread use, which concentrate upon ruggedness, reliability, ease of cleaning and rather precise portion control, at the expense of turning out portions which are so dense and uniform in appearance that much of their relationship to the appearance and texture of the comparable homemade or hand formed product is lost.
To some, such standardized, dense, highly-worked food products suggest the appearance, if not the taste, of hockey pucks.
Typically, such uniformly dense, uniformly shaped patty products are formed by squeezing a column of very cold ground meat into a slotted plate that is slidably mounted in a confined space, then sliding the plate to a second position in which the patty or patties can be displaced from the slot or slots onto a moving conveyor belt.
Up to a point, the forming characteristics of such a machine are improved by lowering the temperature of the ground meat. However, as colder meat is run, generally the pressure on the meat must be increased, e.g. from 150 psi up to 600 psi, in order to ensure filling the slots in the slotted plate. The capability of using higher pressure not only requires the conventional machines to be ruggedly built, but also to need heavy duty electrical service, e.g. a 50 amp/460 volt/3 phase power line. The more severely that a material such as ground beef is caused to flow under pressure, the more proteinaceous juice is expressed from the patties causing a decline in the juiciness, and perhaps in the nutritional quality of the patty, upon cooking.
With the passage of time and the gaining of experience with the conventional machinery, certain adjuncts to the patty-forming process have become fairly standardized throughout the industry. For instance, the conveyor belt width running from where the patties are deposited, into and through the blast freezer to a packing line generally lies in the range of 24-30 inches. Meat grinding machines in most widespread use, e.g. made by Wolfking, Weiler, Hobart or Butcher Boy, generally provide a column of ground meat which is 8-14 inches in diameter (ten inches in diameter being most common), in which the ground meat has been forced through a grid of openings which are each 2.5 mm (3/32 inch) in diameter, although some conventional processes can use more roughly cut meat, e.g. which has been forced through 3.2 mm (1/8 inch) holes. Where the input capacity of a patty former is not matched one-to-one with a grinder, it is known in the art to feed more than one patty former using one grinder or to serve a patty former with more than one grinder, e.g. one serving two, three serving two, etc.
Most cryogenic freezers in widespread use have a design capacity of about 3,200 pounds of ground meat per hour, where the input is at approximately 31.degree.-32.degree. F. and the output is at approximately 5.degree. F. In practice, the freezer serving a patty former often is the limiting factor on throughput of the line. Thus, down to a point where the ground meat is too stiff to be formed on the patty former, the effective capacity of the line can be increased by using colder ground meat as input. For most slotted plate-type hydraulic formers, 31 degrees is about the coldest ground meat can be and still be formed satisfactorily.
An advantage that slotted plate-type hydraulic formers have over some competing patty formers is the ability to form circular or oval patties that, after being cooked, cover a bun more neatly, yet without producing an excess of inter-patty scrap for recycling at the patty forming station.
There are, or have been commercially offered patty formers where the ground meat is sheeted on a conveyor belt, then stamped cookie cutter-fashion, but such machines do suffer in comparison because of the inter-patty scrap that they produce (and because of the problems associated with maintaining properly coordinated timing for the stampers relative to the conveyor belt on which the sheeted meat is moving).
There also are or have been commercially offered patty formers where the ground meat is sheeted on a conveyor belt then slit longitudinally into ribbons and cut crosswise, e.g. by a rotating wheel with transverse cutter bars projecting on its periphery. This avoids inter-patty scrap, but at the cost of producing patties which are either square or rectangular. In actual consumer panel preference testing known to the present inventors, a strong lack of preference for hamburgers in such shapes is almost universally expressed. And poor bun coverage results, where the hamburger bun is traditionally circular in plan outline, either the corners of the square hamburger stick out, or else there are four D-shaped areas about the bun perimeter where there is no meat between the top and bottom halves of the bun. Accordingly, for many processors, use of such equipment is totally impractical.
In the biscuit making industry, it has been known to sheet dough onto a horizontal conveyor belt and to run a cutter wheel in engaging relation with the upper face of the conveyor belt, with the cutter wheel being provided with a honeycomb (completely ordered hexagonal) endless pattern of cutters on its outer peripheral surface. There are two basic reasons why such a cutter works well with biscuit dough but would be impractical to use with sheeted ground meat.
First, when the dough is cut in such a manner, the sheet of dough is comparatively thin. There is not much thickness of sheet for the cutters to clear as they enter and leave the dough, so scarring is minimal. The individual cut hexagonal biscuit blanks are allowed to proof after cutting has been accomplished. Minor scarring is obliterated as the biscuit blanks rise. With sheeted meat, the sheet is comparatively thicker, i.e. substantially the thickness of the desired patty, there being no possibility of using a leavening agent to cause the meat patties to gain in thickness after they have been cut.
Second, while it is permissible and a widespread practice in biscuit making to dust the dough blanks with a coating of vegetable oil and coarse flour which, in addition to aiding in sealing against leavening gas loss and preventing biscuit-to-can and biscuit-to-biscuit sticking, also acts as a cosmetic to further obscure any minor scarring that was caused by the entry and exit of the cutting elements on the rotary cutter wheel. However when making ground meat patties, dusting with a particulate cereal-based material would hardly produce a sufficient cosmetic effect, unless it were applied to such a thickness as to constitute a breading, and, in any event, the addition of a cereal to an all meat product would require advertising and labeling changes that would place the food seller at a competitive disadvantage. (Competitors with all-meat products would not fail to make the point that the other product had been extended with a cereal-based filler, and therefore was of lower quality.)